TassieTiger wrote:Mate a I’m finding very similar things with my press and it is doing my head in.
I expect that once a seating die is locked off, if the case length is exactly the same then the case base to ogive should be exactly the same each time - but I’m getting variances beyond what I’d expect - certainly beyond the 20 thousandth one would use as a starting point from lands.
I’ve actually found that the turret press I use, has a few mm of movement up/down/left/right depending on which way I swing on the handle and I think this is where my issue lies - I’d pay close attention to your mounting, your press, your die...etc.
I’ve noticed that if my shell holder sits in one direction vs 90degs - I get a different reading as well...
SCJ429 wrote:If you are loading for competition you can load to jam +20 thou. This ensures all bullets are jammed even of the ogive lenght varies slightly. Don't do this for hunting rounds as you can leave a bullet stuck in the lands if you remove an unfired round.
New or tumbled clean brass is very grippy, I lube the inside neck with graphite to reduce the grip. The carbon from a fired case will do this job for you.
I deliberately only partially seat a bullet and the turn the case in the die before seating it the rest of the way. I am trying to minimise runout by doing this. I have not seen any changes brought by inconsistent neck tension by doing this.
If you really want to try to have consistant neck tension you should neck turn. Even Lapua cases will benefit from this.
Ziad wrote:How are u measuring the total length. With a vernier to the point/tip of the projectile (coal) or with a hornady bullet comparitor or similar which measures the ogive.
The tip measurement can change even for same bullet.
trekin wrote:Outside the box here, but first off I would be checking the documemntation that came with whatever you are using to messure, I'm assuming a vernier callipers, for the +/- tolerances. Most digital/cheaper ones have a +/- 0.010 tolerance.
Madang185 wrote:You might find that there is a length difference between the base of a projectile and the ogive. I have measured up to .005 difference between commercial boat-tailed projectiles. Flat based projectile are in my experience more predictable and a good batch will be within .001 of each other.
SCJ429 wrote:My experience with Berger bullets is that they are so good that batching them is not needed. When I use Sierra MK, then batching is beneficial.
I have found flat based bullets have an advantage out to 300 metres, for 500 and beyond the boat tail design with its better BC is the best choice.
What are you using your Creedmoor for?
cirles wrote:New to reloading, so this is where I have progressed to so far with new brass. Will multiple re seating of a case (dummy(s) in this situation), in other words incrementally pushing down the projectile to desired measurement (CBTO), stuff the neck tension up so that you get different measurements from other cases which had been subjected to the same thing (long story) from a Seating Die? Will not lubricating inside or outside of the case neck cause this issue? All 4 dummys cases have width measurements of the neck after seating within 6/10 thousandths (0.0006) of an inch (micrometer measurements), so seem to be within margins. CBTO measurements vary up to 10 thousandths (0.0100) of an inch difference (2.2510, 2.2545, 2.2610, 2.2615 inches). Press is Forster Co-Ax.
Apollo wrote:Just a few points I have picked up and not sure what you are doing or using.
The Bullet Seating Die - Does it have a seating insert designed for seating VLD Bullets (Secant Ogive) or is it the standard Tangent Ogive type that just maybe allowing the bullet meplat to touch the bottom of the seating stem rather than use the ogive.
You could try using one of these on your Calipres to give you a greater footprint for measuring.
http://brtshooterssupply.com.au/product ... -base.html
Unless you have a specific Wall Thickness Micrometer like one of these you are not going to get accurate measurements of case wall thickness. The blade of a calipre isn't going to give you very accurate readings, especially the further into the case neck you try and measure.
http://brtshooterssupply.com.au/product ... 1inch.html
Measuring bullet diameters you really need to be using a very accurate micrometer and take one measurement on the bearing surface of the bullet then another near the base of the bullet at the pressure ring which should be a greater measurement. I use one of these...
http://brtshooterssupply.com.au/product ... 1inch.html
This is all getting very expensive and really only to be considered if you are doing competition precision target shooting or you have plenty of money and just like getting things as exact as possible.
If you are seating, removing and re-seating a bullet in the same case you are going to reduce neck tension as every time you seat a bullet you are expanding the case neck ever so slightly unless you size the case neck every time and each time you do that you are hardening the case neck ever so slightly hence producing a slight amount of spring back compared to a case that has not been touched.
In my view every new (unfired) case should be full length resized to make sure they are all the same, then have a mandrel run down the case neck to expand evenly all cases and then have the neck sized to try and create an even set of cases. In my case I anneal every case every reload using an induction annealer set to give the best annealing I can achieve.
I have measured hundreds of Lapua cases and using the measuring equipment listed above I'll tell you that they are not all the same dimensions even over the same box batch lot. They all have differences and also hence why I skim turn case necks even if the chamber size doesn't require neck turning. Also, you really don't want to get into measuring neck thickness until the case has been fireformed and even fired at least twice as the neck material is still moving around the neck diameter.
If you want to be playing with getting bullet seating correct with being exact say 0.020" off the lands then you need a better measuring system for CBTO measurements like a dedicated measuring case and the appropriate guage to measure it like...
http://brtshooterssupply.com.au/product ... aight.html
Unless you are shooting precision target competition I wouldn't really worry about your 0.010" difference you are getting as long as your loaded rounds fit your magazine and bullets are off the lands so your setting of 0.020" gives you that safety margin. If you want to chase the best accuracy the you may want to consider single shot loading rounds that are say jammed 0.020" to jumped quite some distance say 0.100" or more then that will tell you where that bullet likes to be seated in your rifle. Who knows, it may be some jump away from the lands.
One thing I see you mentioned that you don't understand is the partial seating of a bullet. That means that you don't seat the bullet all the way into the neck in one go, say 50% then rotate the case/bullet say 90 degrees and seat the rest of the way.
I don't use the type of press you are using. All my precision reloading is done with In-Line Dies and an Arbor Press.
Hope all this helps a little with your reloading.
marksman wrote:cirles wrote:New to reloading, so this is where I have progressed to so far with new brass. Will multiple re seating of a case (dummy(s) in this situation), in other words incrementally pushing down the projectile to desired measurement (CBTO), stuff the neck tension up so that you get different measurements from other cases which had been subjected to the same thing (long story) from a Seating Die? Will not lubricating inside or outside of the case neck cause this issue? All 4 dummys cases have width measurements of the neck after seating within 6/10 thousandths (0.0006) of an inch (micrometer measurements), so seem to be within margins. CBTO measurements vary up to 10 thousandths (0.0100) of an inch difference (2.2510, 2.2545, 2.2610, 2.2615 inches). Press is Forster Co-Ax.
without reading all posts IMO yes
in practice I have found that different neck tensions will cause different measurements
think about it if a bullet is harder to seat it will and does not seat to the same oal as one that slips in easy, the harder to seat projectile will leave a ring impression on the ogive, the difference may be a couple of thou, powder compression can make a difference as well
I have a force dial on my press that shows differing forces used to seat bullets in different cases that shows the different neck tension and oal
you have to understand that sizing brass or seating and pulling bullets can make the brass harder although when pulling a bullet you will make the neck looser as it has been stretched to the size of the bullet that had been seated
and when try to get your oal on a dummy by making small adjustments to the die will get that oal right but the next one you try at that setting will usually be different but only just so most people will make a dummy and use it for setting up the die but give a quarter turn more before seating
if you are seating close to the lands you will need consistency but if you jam or jump you wont have to be so uniform
you must also consider that bullet ogives do vary so it is beneficial to check and batch bullets for consistent oal's
I hope this helps
Apollo wrote:If this is what you have then you should be right as far as the seating stem goes... See description.
https://brtshooterssupply.com.au/produc ... r-die.html